(a) Field
Exemplary embodiments of the invention relate to a device and method for driving a liquid crystal display.
(b) Description of the Related Art
A liquid crystal display, which is one of the most widely used types of flat panel display, typically includes two display panels, in which field generating electrodes such as a pixel electrode and a common electrode are provided, and a liquid crystal layer interposed between the two display panels.
The liquid crystal display applies a voltage to the field generating electrodes to generate an electric field in the liquid crystal layer, determine alignment of liquid crystal molecules of the liquid crystal layer by the electric field, and control the polarization of incident light to display an image.
The liquid crystal display includes a thin film transistor, a gate line and a data line provided on a display panel of the liquid crystal display including the thin film transistor, and a pixel corresponding to a region for displaying a screen connected to the thin film transistor.
When a gate-on voltage is applied to the gate line and the thin film transistor of a pixel connected to the gate line is thereby turned on, a data voltage applied through the data line is charged in the pixel. In the liquid crystal display, the alignment of the liquid crystal molecules in the liquid crystal layer is determined by an electric field generated by a pixel voltage charged in the pixel and a common voltage applied to a common electrode. The data voltage may be applied with different polarities for each frame.
The data voltage applied to the pixel is reduced by parasitic capacitance between a gate electrode and a source electrode, and the reduced data voltage becomes a pixel voltage. A voltage difference between the data voltage and the pixel voltage will be referred to as a kickback voltage.
The kickback voltage is changed based on a grayscale level and a polarity of the data voltage, and changes the pixel voltage for each frame. Accordingly, a flicker caused by a luminance difference may be observed, and the liquid crystal layer may be influenced by a residual direct current (“DC”) voltage to generate an afterimage.